European Commission Vice President Frans Timmermans told delegates that the European Union will update its climate commitment as it will be able to exceed its original plan to cut emissions by 55 percent by 2030.
The 27-nation bloc will now be able to cut greenhouse gas emissions by 57 percent from 1990 levels, he said.
"The European Union is here to move forwards, not backwards," Timmermans told COP27 delegates.
Campaigners on Tuesday urged leaders at the COP27 summit and big tech companies to formally crack down on climate disinformation that undermines efforts to limit the deadly impacts of global warming.
In an open letter, they called on COP27 delegates to adopt a common definition of climate disinformation and misinformation and work to prevent it.
"We cannot beat climate change without tackling climate misinformation and disinformation," they wrote.
"While emissions continue to rise, humanity faces climate catastrophe, yet vested economic and political interests continue to organise and finance climate misinformation and disinformation to hold back action."
They demanded "swift and robust global action from COP decision-makers and tech platforms to mitigate these threats".
The letter was signed by 550 groups and individuals, including former UN climate chief Christiana Figueres and diplomat Laurence Tubiana, one of the architects of the 2015 Paris Agreement, which is the current basis for global targets to curb climate change.
The COP27 conference in Egypt has been dominated by calls for wealthy nations to fulfil pledges to fund the green transitions of poorer countries least responsible for global emissions, build their resilience and compensate them for climate-linked losses.
The meeting comes as global emissions are slated to reach an all-time high this year, making the aspirational goal of limiting warming to 1.5 degrees Celsius compared to preindustrial levels ever more elusive.
The invasion of Ukraine by fossil fuel exporter Russia has cast a shadow over the talks in Egypt, with activists accusing Europeans of seeking to tap Africa for natural gas following Russian supply cuts.
But Timmermans denied that the 27-nation bloc was in a "dash for gas" in the wake of the Ukraine conflict.
"So don't let anybody tell you here or outside that the EU is backtracking," he said.
"This small increase announced today at COP27 doesn't do justice to the calls from the most vulnerable countries at the front lines," said Chiara Martinelli, of Climate Action Network Europe.
"If the EU, with a heavy history of emitting greenhouse gases, doesn't lead on mitigating climate change, who will?"
UN climate talks often go into overtime and this year's meeting, due to end on Friday, could be no different.
The first draft of the final declaration only has bullet points so far, with a line on the "urgency of action to keep 1.5C in reach".
Wealthy and developing nations are sharply divided over money at COP27.
Developing countries says this year's floods in Pakistan, which have cost the country up to $40 billion, have highlighted the pressing need to create a "loss and damage" compensation fund.
But Western governments favor using existing financial channels instead of building a new mechanism.
The draft declaration mentions the "need for funding arrangements to address" loss and damage -- language used by the United States and Europeans since COP27 started on November 6.
"Loss and damage must remain firmly on the table as we continue to witness increasing appearances of severity of climate change impacts everywhere," Samoan Prime Minister Fiame Naomi Mata'afa told delegates.
"The financial burden for loss and damage falls almost entirely on affected countries and not those most responsible for climate change."